﻿using EU.Core.Common;
using Castle.DynamicProxy;
using EU.Core.Common.Caches;

namespace EU.Core.AOP;

/// <summary>
/// 面向切面的缓存使用
/// </summary>
public class TiobonCacheAOP : CacheAOPbase
{
	//通过注入的方式，把缓存操作接口通过构造函数注入
	private readonly ICaching _cache;

	public TiobonCacheAOP(ICaching cache)
	{
		_cache = cache;
	}

	//Intercept方法是拦截的关键所在，也是IInterceptor接口中的唯一定义
	public override void Intercept(IInvocation invocation)
	{
		var method = invocation.MethodInvocationTarget ?? invocation.Method;
		//对当前方法的特性验证
		//如果需要验证
		var CachingAttribute = method.GetCustomAttributes(true).FirstOrDefault(x => x.GetType() == typeof(CachingAttribute));
		if (CachingAttribute is CachingAttribute qCachingAttribute)
		{
			//获取自定义缓存键
			var cacheKey = CustomCacheKey(invocation);
			if (_cache.Exists(cacheKey))
			{
				//将当前获取到的缓存值，赋值给当前执行方法
				Type returnType;
				if (typeof(Task).IsAssignableFrom(method.ReturnType))
				{
					returnType = method.ReturnType.GenericTypeArguments.FirstOrDefault();
				}
				else
				{
					returnType = method.ReturnType;
				}

				//根据key获取相应的缓存值
				dynamic cacheValue = _cache.Get(returnType, cacheKey);
				invocation.ReturnValue = (typeof(Task).IsAssignableFrom(method.ReturnType)) ? Task.FromResult(cacheValue) : cacheValue;
				return;
			}

			//去执行当前的方法
			invocation.Proceed();
			//存入缓存
			if (!string.IsNullOrWhiteSpace(cacheKey))
			{
				object response;

				//Type type = invocation.ReturnValue?.GetType();
				var type = invocation.Method.ReturnType;
				if (typeof(Task).IsAssignableFrom(type))
				{
					dynamic result = invocation.ReturnValue;
					response = result.Result;
				}
				else
				{
					response = invocation.ReturnValue;
				}

				if (response == null) response = string.Empty;

				_cache.Set(cacheKey, response, TimeSpan.FromMinutes(qCachingAttribute.AbsoluteExpiration));
			}
		}
		else
		{
			invocation.Proceed(); //直接执行被拦截方法
		}
	}
}